1. Field of the Invention
The present invention relates to the development of outside plant cables to be used in Voice, Video, Data and Distribution (VVDD) type communications, and specially to telephone cables with larger bandwidth operation levels while maintain or preserve operation frequencies for voice transmission.
2. Previous Art
Currently, the telecommunication cables for interior use based on metal conductors with polyolefin insulation, formed into pairs and without shielding insulating them against electromagnetic interferences have had an accelerated development. Thus, they can currently work in frequencies ranging up to 250 MHz, according to the Nema WC 66-99 American Standard specification. Said cables are basically focussed on local area networks (LAN), houses, department buildings, or industrial structures, public buildings, intelligent buildings or school centers. This growth of local area networks has provoked that the users of digital services such as Internet, video on demand, high definition television, teleconferences, voice and fax services request telephone networks flexible enough to offer said services with a higher quality and faster transmission speeds compared to the ones handled currently in the outside plant telephone cables which have remained without important technical changes.
Innovations regarding telecommunication cables are known. For example, U.S. Pat. No. 5,739,473 describes a flame retardant telecommunication cable for office building use; said cable has a conductor array insulated in groups of twisted pairs and the insulation used in the core group is different from the insulation used in the surrounding groups. The main characteristic of this system is its structure and the use of a fluorinated copolymer. U.S. Pat. No. 4,319,071 describes a cable for telephone communication purposes with high multipair with small conductors the main characteristic of which is a liquid filling based on waterproof paraffin oils.